Aqueous solution of polyvinyl alcohol containing insoluble starch derivative and proces of preparing fibers therefrom



United States Patent C) AQUiEDUS SOLUTION F POLYVINYL ALCOHOL Thisinvention relates to a process of producing fibers of polyvinyl alcoholand is more particularly concerned with a process of forming such fiberswhich are characterized by desired properties.

As described in US. patent application Serial No. 856,334, filedDecember l, 1959, now US. Patent 3,007,228, dated November 7, 196d, thedyeability of polyvinyl alcohol fibers can be markedly increased byspinning the fibers from a mixture of an emulsified polymer formed frombasic monomers and a water solution of poly-vinyl alchool. When fibersspun from such a mixture are subjected to heat-treatment andbenzalization, fibers can be obtained which have excellent dyeability.It has also been found that the same effect can be obtained when anemulsion or a fine powder of waterinsolu-ble polyvinyl alcoholderivatives obtained by acetalization of polyvinyl alcohol withaldehydes having basic nitrogen, and, if necessary, by acetalizationwith aldehydes having no basic nitrogen at the same time, or before orafter the first acetalization, are moved with a water solution ofpolyvinyl alcohol, followed by spinning and heat-treatmtent andbenzalization of the fibers.

It is an object of this invention to provide a process for producingfibers of polyvinyl alcohol having high hotwater resistance andheat-resistance and desirable mechanical properties at least equal tofibers produced solely from polyvinyl alcohol, yet characterized by aparticularly high dyeability.

In accordance with this invention, spinning of fibers is effected from aspinning fluid prepared by dispersing in a water solution of polyvinylalcohol an emulsion or fine powder of water-insoluble starch derivativescontaining basic nitrogen introduced into the starch molecule byetherification with epoxy compounds containing basic nitrogen,ethyleneimine or its derivatives, or B-aminoethylsulfuric acid.

We have studied extensively the manufacture of emulsions or fine powderof polymers which are water-insoluble and contain basic nitrogen. Wehave found that the desired objective can easily be achieved by spinningfibers from the spinning fluid composed ofta water solution of polyvinylalcohol in which has been mixed and dispersed emulsion or fine powder ofWater-insoluble starch derivatives containing basic nitrogen introducedby etherificatio-n with epoxy compounds containing basic nitrogen,ethyleneimine or its derivatives, or El-aminoethylsulfuric acid, andthat the dyeability of such fibers, particularly afterbenzalization,have a greatly improved dyeability compared with polyvinyl alcoholfibers alone.

In the methods described in said application Serial No. 856,334, theparticle sizes produced are below 0.5a, and it is very difficult tochange the particle size. In accordance with the present invention,however, the waterinsoluble starch derivatives containing basic nitrogencan be produced with any desired particle size by selecting 3,067,152Patented Dec. 4, 1962 if necessary, so as to conform with the denier ofthe fiber to be manufactured, as well as the color-fastness and physicalproperties required in the fiber. In case of such mixed spinning, andwhen the fiber is given an insolubilization treatment e.g.acetalization, after heattreatment, fine particles of the starchderivatives containing basic nitrogen as dispersed in the fiber and aredifficultly influenced by the hydrophobic character imparted to thefiber by acetalization. Particularly when acetalization is effected withbenzaldehyde, a portion of the polyvinyl alcohol molecule will haveimparted to it hydrophobic p-roperties as benzalization progresses andthis serves to promote the elasticity of the fiber itself, but the fine.particles of the starch derivatives containing basic nitrogen are notthus affected by the benzalization reaction despite the fact that theycontain hydroxyl groups. As a result, the hydrophilic propertyindispensable for dyeability is not changed even after the benzalizationtreatment. Hence, the fiber has very good dyeability.

However, when the particle size is unduly large, broken or nappyfilaments may result at the time of spinning, with subsequentdeterioration of the physical and mechanical properties of the fiber.Hence, it is important to restrict the size of the particles to below 30 1. diameter.

The amount of basic nitrogen introduced into the starch molecule issuitably 0.02%'3% by weight. When a mixture of such starch derivativesand polyvinyl alcohol are spun, a marked elevation in dyeability 0f theresultant fibers is observed with direct cotton dyes and acid wool dyes.

To form a stable dispersion of the above-described solid polymerparticles in a water solution of polyvinyl alcohol, various proceduresmay be employed. Thus when the starch derivative is in the form of anemulsion, the emulsion may be directly mixed with a water solution ofpolyvinyl alcohol, or it may be mixed with polyvinyl alcohol powder andwater may then be added to dissolve the powder. Alternatively, theemulsion may be heated, and polyvinyl alcohol powder or moist polyvinylalcohol powder may be slowly added and dissolved in the emulsion. Whenthe starch derivative particles are in the form of a fine powder, thepowder particles may be mixed with polyvinyl alcohol powder and wateradded to dissolve the powder mixture or the starch derivative particlesmay be mixed with a small amount of water or a water solution ofpolyvinyl a1- cohol, and the paste of fine powder thus obtained may bemixed with polyvinyl alcohol. It will be understood, however, thatvarious other procedures may be used. If desired, any of the variousknown surface active agents or protective colloids may be added to thesolution. As surface active agents, various anionic, non-ionic, andcationic surface active agents are suitably used, but in asmuch as ananionic surface active agent may occasionally tend to coagulate solidparticles by forming a bond with basic nitrogen, it is preferred to usea nonionic surface active agent such as polyoxyethylenedodecyl ether, ora cationic surface active agent such as dodecyltrimethylamrnoniumchloride. As protective colloids, compounds such as water-solublestarch, partially aminoacetalized polyvinyl alcohol, and the like aresuitably used.

The fiber spun by the method of this invention may be subjected tothermal elongation, i.e. hot-stretching, heat-treatment andinsolubilization treatments in the same manner as fibers formed solelyfrom ordinary polyvinyl alcohol. For effecting insolubilizationtreatments there may be employed acetalization by means of aldehydessuch as formaldehyde, acetaldehyde, chloracetaldehyde, butylaldehyde,nonylaldehyde, benzaldehyde, mono chlorbenzaldehyde, l-naphthaldehyde,glyoxal, malonan autoclave at 130 C. for 3 hours.

aldehyde, glutaraldehyde, terephthaldehyde, and the like. The fibers mayalso be subjected to treatments with inorganic reagents such astitanation, and chroming. Various other known insolubilizationtreatments may also be employed.

It is also preferable to carry out spinning by means of the spinningfluid prepared by dispersing an emulsion or a fine powder of the starchderivatives with polyvinyl alcohol by the method of this invention, withthe addition of various types of water-soluble polymers such as solublestarch, polyvinylpyrrolidone, aminoacetalated polyvinyl alcohol, variouskinds of pigments such as titanium oxide, and acids, alkalis, and saltssuch as sodium sulfate, and the like. Accordingly, it is possible tosimultaneously effect improvements in the transparency and in the formof the cross-section of the fibers particularly when the fibers areformed by wet spinning.

Compounds containing basic nitrogen suitable for use in accordance withthe method of this invention include epoxy compounds containing basicnitrogen which may be formed by the reaction of epichlorohydrin with anyalkyl or cycloalkyl secondary amine such as diethylamine, dibutylamine,didodecylamine, dihexylamine, methyl-ethylamine, cyclohexylamine,ethyl-butylamine, ethyleneimine, and the like, any of the derivatives ofethyleneimine having the ethyleneimine ring such as those formed by thereaction of ethyleneimine with melamine and phosphoric acid, and thelike, and compounds such as fieamino-ethyl sulphuric acid.

The starch usable in the method of the present invention, is any of theknown starches such as potato starch, Japanese arrowroot starch, sweetpotato starch, wheat starch, rice starch, corn starch, tapioca starch,arrowroot starch (maranta starch) sago starch and like substances havingthe starch molecular structure. In addition, starch derivatives, such asacetyl starch, may be used.

The invention will be further understood from the following specificexamples of practical application. However, it will be understood thatthese examples are not to be construed as limiting the scope of thepresent invention in any manner. In these examples, all parts are byweight, unless otherwise indicated.

Example 1 Ten grams of Wheat starch (particle size: 2-3 1) werethoroughly mixed with 2 g. of l-dimethylamino- 2,3-epoxypropane. Themixture is allowed to react in The reaction product was then thoroughlywashed, and unreacted l-dimethylamino-2,3-epoxypropane was removed. Thewere thus obtained in the form of fine particles, a wheat starchderivative containing basic nitrogen. These fine particles weredispersed in water to form a water dispersion and thus a slightlyviscous emulsion was obtained.

This emulsion of fine particles was mixed with polyvinyl alcohol in theamount of 10% of particles based on the polyvinyl alcohol and thepolyvinyl alcohol was dissolved by the addition of further quantities ofWater. The resultant solution was wet-spun into a sodium sulfatecoagulation bath, and the fibers were subjected to heat-treatment at 235C. for 30 seconds at a fixed yarn length. The heatatreated fibers werebenzalized in a water solution containing benzaldehyde (1.5%), sulfuricacid and methanol (40%) at 60 C. for 4 hours. The degree ofbenzalization after the treatment was 32.0%.

When these fibers were dyed with Acid Brilliant Scarlet 3R (4%) andsulfuric acid (3%) (percentages by Weight based on the fiber to be dyed)with a bath ratio of 1:100 at 90 C. for one hour, the dyestulf wascompletely absorbed with no sign of any drop in dyeability when comparedwith dyed heat-treated fiber.

An optical microscopic observation of the cross sec tion and the sidesof the dyed fibers revealed the presence of dyed fine grains.

Example 2 Ten grams of potato starch (particle size: 2-3 t) were mixedwith 3 g. of ethyleneimine and the mixture was reacted in an autoclaveat 130 C. for 3 hours. The product obtained, which was a starchderivative containing basic nitrogen and was in fine powder form, wasthoroughly washed to remove unreacted ethyleneimine, and by air-drying,a fine powder with a water content of 15% was obtained having a basicnitrogen content of 1.5%.

The fine powder was thoroughly mixed and dispersed with polyvinylalcohol in the proportion of 10% of powder based on the polyvinylalcohol and water was added to prepare a spinning fluid with a polyvinylalcohol content of 30%. This spinning fluid was forced into hot air toefiect dry-spinning in conventional manner and polyvinyl alcohol fiberswere produced. After hotstretching by 500% at 230 C. at fixed yarnlength, the fibers were heat-treated at 235 C. for 10 min. Some of theheat treated fibers thus obtained were formalized in a water solutioncontaining formaldehyde (5%) and sulfuric acid (15%) at 70 C. for twohours, and the remaining fibers were benzalized in a water solutioncontaining benzaldehyde (2%) and sulfuric acid (15 and methanol (40%)for two hours. The degree of acetalization grade was 42.0% and 31.0%,respectively.

When samples of these fibers were dyed in a dyeing bath consisting ofAcid Brilliant Scarlet 3R, an acid dye (4), and sulfuric acid (3%)(percentages by weight based on the fiber to be dyed), or in a dyeingbath consisting of Sunchrome Brown RH (4%) and sulfuric acid (3%)(percentages by weight based on the fiber to be dyed) at C. for onehour, this mordant dye being developed by the use of potassiumbichromate, the dyestufis were completely absorbed in the case of boththe formalized and the benzalized fibers.

Before spinning, the spinning fluid was heated to 150 C. under apressure of 10 kg./cm. but nothing abnormal was observed as to thecondition of either the dispersion of fine grains or their particlesize.

Example 3 With 10 g. of arrowroot starch (particle size: 1-2;/.), weremixed 5 g. of 1-diethylamino-2, 3-epoxypropane, and the mixture wasdissolved and dispersing in dioxane (50 cc.). The solution was allowedto react in an autoclave at 90 C. for 5 hours. After the reaction wascompleted, the reaction mixture was filtered and washed and there wasrecovered a fine powder consisting of a starch derivative containingbasic nitrogen. The basic nitrogen content being 1.2%.

This fine powder was mixed with polyvinyl alcohol in the amount of 15%based on the polyvinyl alcohol and a spinning solution was formed andspun as in Example 1 and the fibers were heat-treated, and acetalized asdescribed in Example 1. When the treated fibers were dyed with thedyestuffs and under the dyeing conditions specified in Example 1, thedyestuffs were found to the completely absorbed by the fibers.

Example 4 A fine powder (particle size: 2-3;) containing basic nitrogenobtained by treating a water solution containing potato starch (10 g.)with fi-amino-ethylsulfuric acid (5 g.) and caustic soda (2 g.) at C.for 2 hours, was mixed with polyvinyl alcohol and spun as described inExample 2 and the resultant fibers were heat-treated and acetalized inthe manner set forth in Example 2. As in the case of the fibers ofExample 2, the fibers thus produced had very good dyeability.

The surface-active or dispersing agents or dispersants and protectivecolloids which are suitably employed are, in addition to those mentionedabove, any of the many dispersing agents and protective colloids knownto those skilled in the art of making emulsions or dispersions ofpolymers. in the foregoing examples, for instance, polyoxyethlenedodecylether is suitably used as the dispersant or surface-active agent.

It will therefore be understood that, unless otherwise indicated,conventional operations and conventional apparatus are employed incarrying out the process of this invention including conventional mixingand emulsifying units. Similarly, conventional dyeing techniques andapparatus are suitably employed upon the fibers produced by the processof this invention. The conditions and the relative relationships setforth in the examples are those preferred in carrying out the process ofthe invention but it will be understood that other conditions andrelationships may be used within the scope of the invention.

The spinning fluids produced in accordance with the present inventionare particularly suitable for the spinning of the fibers in accordancewith known processes used in the spinning of polyvinyl alcohol andpolyvinyl alcohol derivatives, particularly the so-called wet-spinningtechniques as described, for example, in Cline et al. US. Patent2,610,360 and Osugi et al. Patent No. 2,906,594. An especially preferredspinning technique is described in copending application Serial No.336,166 of Tomonari et al. filed February 10, 1953, now US Patent2,988,802, dated June 20, 1961.

After formation of the fibers by Wet spinning the fibers can be furthertreated by stretching, heat-treating, acetalization, and the like toproduce fibers with desirable and outstanding properties, using knowntechniques as described in said patents.

Examples of starches and starch derivatives suitable for use in theinvention have been given above, but it will be understood that any ofthe known starches and starch derivatives, such as these described inStarchlts Sources, Production and Uses by Charles A. Brantlecht(Reinhold Publishing Corp.) may be used.

It will also be understood that various changes and modifications inaddition to those indicated above may be made in the embodiments hereindescribed Without departing from the scope of the invention as definedin the appended claim-s. 'It is intended, therefore, that all 6 mattercontained in the foregoing description shall be interpreted asillustrative only and not as limitative of the invention.

We claim:

1. A process of producing fibers of polyvinyl alcohol of improvedproperties which comprises adding to an aqueous solution of polyvinylalcohol, water insoluble starch derivatives with a particle size below30p, mixing and dispersing said derivatives in said solution andspinning said fibers from the resultant spinning solution, saidderivatives containing 0.02% to 3% by weight of basic nitrogen and beingthe products resulting from reaction of starch with a member of thegroup consisting of epoxy compounds containing basic nitrogen andobtained by the reaction of epichlorohydrin with secondary aminesselected from the group consisting of alkyl amines and cycloalkylamines, ethylene-imine, the reaction product of ethylene-imine withmelamine, the reaction product of ethylene-imine with phosphoric acid,and fl-amino ethyl sulfuric acid.

2. A polyvinyl alcohol spinning solution effective to provide fibers ofpolyvinyl alcohol of improved properties formed by adding to an aqueoussolution of polyvinyl alcohol, water insoluble starch derivatives with aparticle size below 30, and mixing and dispersing said derivatives insaid solution, said derivatives containing 0.02% to 3% by weight ofbasic nitrogen and being the products resulting from reaction of starchwith a member of the group consisting of epoxy compounds containingbasic nitrogen and obtained by the reaction of epichlorohydrin withsecondary amines selected from the group consisting of alkyl amines andcycloalkyl amines, ethylene-imine the reaction product of ethyIene-iminewith melamine, the reaction product of ethylene-imine with phosphoricacid, and fi-amino ethyl sulfuric acid.

References Cited in the file of this patent UNITED STATES PATENTS2,265,283 Herrmann et a1. Dec. 9, 1941 2,808,380 Olsen Oct. 1, 19572,906,594 Osugi et al. Sept. 29, 1959 UNITED STATES PATENT OFFICECERTIFICATE OF Patent No. 3 067 152 CORRECTION December 4,, 1962 OsamuFukushima et alo It is hereby certified that error appears in the abovenumbered patent requiring correction and that the said Letters Patentshould read as corrected below Column I line 18,, for desired readdesirable line 25 for "'alchool" read alcohol =-=g line 35 for movedread mixed line 37 for "'heat=treatmtent" read heattreatment column 3,,line 550 for "The" read There column 4 line 29 for "(4) read (4%) 'thefirst oceurrence read be 2 for "'polyoxyethlenedodecvl" read column 6line 25 for 30 read Signed and sealed this 23rd (SEAL) Attest:

ERNEST w. SWIDER Attesting Officer line 59 for column 5 lines 1 andpolyoxyethylenedodecyl day of July 1963o DAVID L. LADD

2. A POLYVINYL ALCOHOL SPINNING SOLUTION EFFECTIVE TO PROVIDE FIBERS OFPOLYVINYL ALCOHOL OF IMPROVED PROPERTIES FORMED BY ADDING TO AN AQUEOUSSOLUTION OF POLYVINYL ALCOHOL, WATER INSOLUBLE STARCH DERIVATIVES WITH APARTICLE SIZE BELOW 30, AND MIXING AND DISPERSING SAID DERIVATIVES INSAID SOLUTION, SAID DERIVATIVES CONTAINING 0.02% TO 3% BY WEIGHT OFBASIC NITROGEN AND BEING THE PRODUCTS RESULTING FROM REACTION OF STARCHWITH A MEMBER OF THE GROUP CONSISTING OF EPOXY COMPOUNDS CONTAININGBASIC NITROGEN AND OBTAINED BY THE REACTION OF EPICHLOROHYDRIN WITHSECONDARY AMINES SELECTED FROM THE GROUP CONSISTING OF ALKYL AMINES ANDCYCLOALKYL AMINES, ETHYLENE-IMINE THE REACTION PRODUCT OF ETHYLENE-IMINEWITH MELAMINE, THE REACTION PRODUCT OF ETHYLENE-IMINE WITH PHOSPHORICACID, AND B-AMINO EHTYL SULFURIC ACID.